Device for controlling ballast and mud for gravel compacted column produced by a wet process

ABSTRACT

The invention relates to a device for controlling gravel and mud for a compacted gravel column made by wet construction using a drilling system fitted with a vibrator, comprising;
         a mud collection element ( 2 ) defining an internal volume capable of collecting mud and fitted with an orifice through which the vibrator will pass, and   at least one gravel guide wall ( 3 ) leading to the orifice ( 5 ) through which the mud collection element ( 2 ) will pass.

The purpose of the invention is a device for controlling gravel and mud for a compacted gravel column made by wet construction

A compacted gravel column is made by drilling into the ground using a drilling system fitted with a vibrator that progressively goes down into the ground until reaching a required depth.

Once the ground has been drilled, gravel is poured into the ground entry orifice (also called the column head) to the bottom of the column where the gravel, possibly compacted by vibrations of a vibrator, forms an inclusion.

Gravel inclusions in the soil make the soil strong, particularly in the case in which a structure will be built on the soil.

A wet construction method can be adopted to facilitate penetration of the vibrator into the soil, in other words water can be injected under pressure at the tip of the vibrator. Soil then disintegrates more easily, and the diameter of the excavation formed will be larger than the diameter of the vibrator.

Injected water is mixed with particles of disintegrated soil and comes out of the compacted gravel column in the form of mud.

It is known that channels and settlement ponds can be excavated to evacuate and treat mud away from the platform on which the boreholes are made.

Even so, the area to be drilled is often flooded and largely covered with mud.

Such a situation creates a risk for the safety of persons working on the site and creates a negative environmental impact.

Another disadvantage lies in the fact that the site requires a large area due to the presence of channels and settlement ponds, which also requires a more complex site organisation.

Furthermore, ground markings made to identify the location of compacted gravel columns to be constructed are lost because the platform is flooded, which wastes time because the ground setting out operation has to be done again.

Moreover, gravel poured at the top of the column is not precise and a non-negligible quantity of gravel can thus be lost in the mud that covers the platform. This makes it difficult to control and check quantities of gravel poured into the columns, and excess consumption of gravel.

The purpose of the invention is to at least partially overcome these disadvantages.

The purpose of the invention to achieve this purpose is a device for controlling gravel and mud for a compacted gravel column made by wet construction using a drilling system fitted with a vibrator, comprising;

-   -   a mud collection element defining an internal volume capable of         collecting mud and fitted with an orifice through which the         vibrator will pass, and     -   at least one gravel guide wall leading to the orifice through         which the vibrator will pass in the mud collection element.

With this device according to the invention, mud is retained in the internal volume of the collection element from where it can be pumped, thus preventing flooding of the platform.

This makes the construction site safer and also limits the impact on the environment.

Moreover, there is no need to provide mud evacuation channels, thus reducing the area occupied by site facilities, eliminating addition activities to clean these trenches, and in general simplifies management of the site organisation.

Moreover, since the platform is not covered with mud, markings on the ground remain visible and the construction work time is optimised.

Moreover, guidance of the gravel firstly makes it possible to pour the required quantity for each inclusion more precisely, and secondly makes it possible to regulate and control the flow and volume of the poured gravel, consequently improving quality due to the control and management of gravel consumption on the site.

According to another characteristic of the invention, the control device includes a guide element provided with said at least one guide wall and a first orifice and a second orifice, the second orifice being the same size as or narrower than the orifice through which the vibrator of the mud collection element passes, the first and second orifices being sized so that the vibrator can pass through them.

Thus, the vibrator can pass through the control device to drill the ground.

According to another characteristic of the invention, the collection element comprises a top face or may not have a top face.

The top face forms a lid of the collection element that improves containment of the mud.

When there is no top face, the content of the control device can be seen directly.

According to another characteristic of the invention, the general shape of the guide element is a truncated pyramid.

According to another characteristic of the invention, the control device includes a mud evacuation module, removing mud from the mud collection element.

According to another characteristic of the invention, the evacuation module comprises at least one pipe, one end of which is located in the inside volume of the mud collection element and the other end is located outside the internal volume of the mud collection element and can be connected to a mud suction pump.

According to another characteristic of the invention, the control device includes a mud suction pump.

According to another characteristic, the control device includes a sealing device between the ground and the mud collection element.

According to another characteristic, the sealing device comprises at least one insertion wall of the control device into the ground.

Thus, when the control device is located at the position to be drilled, once the insertion wall has been pressed into the ground, a seal is created that prevents mud losses outside the control device.

According to another characteristic of the invention, the control device includes at least one slinging point.

It is thus easy to displace the control device with the vibrator (using the slinging points), or independently of the vibrator (sling, fork, vehicle).

Another purpose of the invention is a gravel and mud control system for a compacted gravel column made by wet construction using a drilling system provided with a vibrator, said system comprising a control device like that described above, a gravel storage tank and a gravel conveyor belt from the storage tank to the gravel and mud control device.

According to another characteristic of the invention, the control system includes a traction means.

Another purpose of the invention is a control system comprising the control device as described or the system as described above, and at least:

-   -   a flow meter to measure the volume of evacuated mud, and/or     -   a gravel volume or mass measuring instrument, built into the         control device.

According to another characteristic of the invention, the system comprises a data collection and recording system, using data supplied by the flow meter and/or the gravel mass measurement instrument.

Another purpose of the invention is a method of constructing a compacted gravel column using a drilling system fitted with a vibrator, comprising a step to displace the vibrator from a rest position into a soil drilling position, characterised in that the displacement step includes a step during which the vibrator passes through the gravel and mud control device as described above.

According to another characteristic of the invention, the method comprises a step before the gravel and mud control device is put into position as described above in a position on the ground to be drilled above a location in which gravel inclusion will be made, the control device being moved independently of the vibrator or moved fixed to the vibrator.

According to another characteristic of the invention, the method includes a step in which the ground is drilled by the vibrator and a step in which gravel is added into the gravel and mud control device as described above, during which the gravel is guided by said at least one guide wall in the hole drilled by the vibrator.

According to another characteristic of the invention, the method includes a step to collect mud obtained after injection of water during the soil drilling step using the vibrator in the internal volume of the gravel and mud control device as described above.

According to another characteristic of the invention, the method includes a step to pump mud outside the gravel and mud control device as described above.

Other characteristics and advantages of the invention will become clear after reading the following description. This description is purely illustrative and should be read with reference to the appended drawings among which:

FIG. 1 illustrates a perspective view of a gravel and mud control device according to a first embodiment of this invention;

FIG. 2a illustrates another perspective view of the control device in FIG. 1;

FIG. 2b illustrates a perspective view of a variant of the control device in FIG. 2 a;

FIG. 3 is a top view of the control device in FIGS. 1 and 2 a;

FIG. 4 is a sectional view on an axis IV-IV of the control device in FIG. 3;

FIG. 5 is a sectional view on an axis V-V of the control device in FIG. 3;

FIG. 6 illustrates a perspective view of a gravel and mud control device according to a second embodiment of this invention;

FIG. 7a illustrates a flipped perspective view of the control device in FIG. 6;

FIG. 7b illustrates a perspective view of a variant of the control device in FIG. 7 a;

FIG. 8 is a top view of the control device in FIGS. 6 and 7;

FIG. 9 is a sectional view on an axis IX-IX of the control device in FIG. 8;

FIG. 10 is a sectional view on an axis X-X of the control device in FIG. 8;

FIG. 11 illustrates a perspective view of a control system fitted with a gravel and mud control device according to a third embodiment of this invention;

FIG. 12 illustrates an elevation view of the system in FIG. 11;

FIG. 13 illustrates a diagrammatic view of another system fitted with a gravel and mud control device according to this invention; and

FIGS. 14, 15 and 16 illustrate steps in a method of making a compacted gravel column using the control device according to this invention.

As illustrated on the figures, a gravel and mud control device 1 for a compacted gravel column made by wet construction using a drilling system provided with a vibrator, includes a mud collection element 2 and at least one gravel guide wall 3.

The mud collection element 2 defines an internal volume 4 that will collect mud, and is fitted with an orifice 5 through which the vibrator will pass.

Each gravel guide wall 3 cooperates with the mud collection element 2 along the direction in which the guide wall 3 is located so as to guide the gravel as far as the passage orifice 5.

The invention will now be described in detail for the first embodiment in FIGS. 1 to 5.

As can be seen on FIGS. 1 to 5, the mud collection element 2 is an open cylinder 6.

On the variant illustrated in FIGS. 2a , 3, 4 and 5, the open cylinder 6 comprises one face 7 called the top face, through which the vibrator passage orifice 5 passes.

The face 7 is in the general shape of a ring.

On the variant illustrated in FIG. 2b , the cylinder 6 is open at both ends, in other words it does not have an open face 7.

According to one variant not shown, a window is formed in the face 7 through which the quantity of mud and gravel inside the internal volume 4 can be displayed.

The open cylinder 6 comprises a side wall 8.

The cylinder 2 is preferably completely hollowed out on the face opposite the top face 7 such that the vibrator can pass through the mud collection element 2 and mud can be collected in the internal volume 4.

As can be seen on FIGS. 1 to 5, the control device 1 comprises a guide element 10.

The guide element 10 is a funnel or a hopper.

In the illustrated embodiment, the hopper 10 comprises four guide walls 3 and is in the general shape of a truncated pyramid.

Each wall is sloped such that the guide element 10 is tapered from an open face 11 to an open base 12.

The face 11 is a virtual surface delimited by the first ends of each guide wall 3, and will contain the gravel.

The guide walls 3 are joined together in a circle delimiting the base 12, and are extended by a cylinder 13 with the same diameter as the circle 12 inside the internal volume 4.

The guide hopper 10 and the gravel guide cylinder 13 are fixed to the mud collection cylinder 2, the circle of the guide walls 3 being inserted in the top face 7 of the mud collection element 2.

In other words, the circle 12 and the cylinder 13 forming the base of the hopper 10 are coaxial with the cylinder 6 of the mud collection element 2.

The face 11 forms a first orifice of the hopper 10 and the base 12 forms a second orifice of the hopper 10. The second orifice 12 is the same size as or is narrower than the orifice 5 through which the vibrator of the mud collection element 2 passes, because the hopper 10 is inserted in the cylinder of the mud collection element 2.

The face 11 and the base 12 are sized so that the vibrator can pass through, and advantageously the face 11 is large than the base 12.

The base of the cylinder 13 stops about 15 centimetres above the ground. The side wall of the cylinder 13 is also perforated with mud passage holes 50. The holes 50 assure that mud can circulate more freely in the internal volume 4 of the cylinder 6 and is consequently more easily sucked outside the internal volume 4. Such a design of the cylinder 13 can optimise the efficiency with which gravel is guided into the hole without forming an obstruction to free circulation of mud.

The control device 1 includes a mud evacuation module 15, removing mud from the mud collection element.

The evacuation module 15 comprises at least one pipe 16, one end 17 of which is located in the inside volume 4 of the mud collection element 2 and the other end 18 is located outside the internal volume of the mud collection element and can be connected to a mud suction pump.

In the embodiment illustrated, the general shape of the evacuation module 15 is a Y and it comprises two pipes 16, the end 17 of which plunges into the internal volume 4 of the parallelepiped 2, and that come together in a single pipe 19.

Preferably, the evacuation module 15 of the device 1 comprises a gravel filter at the end 17 (that can for example be seen on FIGS. 3 and 5) to prevent gravel from being drawn in with the mud that is advantageously composed of a simple grid fixed on the internal orifice (as shown) or a more elaborate strainer.

The mud pump (not shown) is either integrated into the control device 1, or it may be independent of the control device 1. As can be seen on FIGS. 1 to 5, the control device 1 also comprises a retaining structure 20 made of a plurality of bars.

The retaining structure 20 comprises a frame comprising four bars 21 a, 21 b, 21 c and 21 d forming a rectangle arranged around the cylinder 6.

The retaining structure 20 provides a stiffener for the device 1 and also gives a better visual delimitation of the device 1, that makes the device 1 safer to use.

The device 1 also comprises two transport ducts 22 for the device 1. The two ducts 22 are configured so that each houses a load support fork.

The two ducts are embedded in the bars 21 a and 21 c provided with fork passage orifices.

The retaining structure 20 also includes four bars 23 each of which runs alongside the top end of the guide walls 3 and form a rectangle.

The retaining structure also comprises four parallel bars 24 connected to each other such that each connects one of the ends of one of the bars 21 a, 21 c, to one of the ends of bars 23.

As can be seen on the figures, the control device 1 comprises at least one sling point 25, and preferably four sling points 25 located at the tops of the rectangle formed by the bars 23, for transport of the control device 1.

Advantageously, the control device 1 includes a sealing device between the ground and the mud collection element 2.

On FIGS. 1 to 5, the leak tightness device comprises at least one insertion wall corresponding to the side wall 8 of the cylinder 6.

Nevertheless, there can be several variants of the sealing device, and for example it may be composed of a rubber seal or a gland.

In the usage position for the construction of a compacted gravel column in soil, as will be explained below for the method according to this invention the control device 1 is placed on the soil.

The face 11 and the base 12 of the guide element 10, and the passage orifice 5 of the upper face 7 of the mud collection element 2 are facing the ground.

The side wall 8 partially penetrates into the ground under the self-weight of the device to create a seal between the control device 1 and the ground. The bars 21 a, 21 b, 21 c, 21 d of the retaining structure 20 lie on the ground.

The invention will now be described in detail for the second embodiment in FIGS. 6 to 10.

Elements identical to elements for the first embodiment have the same references as for the first embodiment.

As can be seen on FIGS. 6 to 10, the mud collection element 2 is an open parallelepiped 6, of which one face 7, called the upper face, is perforated with an orifice 5 through which the vibrator passes.

According to the variant illustrated in FIG. 7b , the cylinder 6 is open at both ends, in other words it does not have an open face 7.

According to one variant not shown, a window is formed in the face 7 through which the quantity of mud and gravel inside the internal volume 4 can be viewed.

The open parallelepiped 6 comprises four lateral faces 8 a, 8 b, 8 c and 8 d.

The parallelepiped 6 is preferably completely hollowed out on the face opposite the top face 7 such that the vibrator can pass through the mud collection element 2 and mud can be collected in the internal volume 4, as will be described below.

As can be seen on FIGS. 6 to 10, the control device 1 comprises a guide element 10.

The guide element 10 is a funnel or a hopper.

In the illustrated embodiment, the hopper 10 comprises four guide walls 3 and has the general shape of a truncated pyramid.

In other words, each wall is sloped such that the guide element 10 is tapered from an open face 11 to an open base 12.

The face 11 is a virtual surface delimited by the first top ends of each guide wall 3, and will contain the gravel, as will be explained below.

The base 12 is the open space defined by eight portions 13 of the wall forming two ends of the guide walls.

The portions 13 are composed of four parallelograms facing each other in pairs, two adjacent parallelograms being attached by a triangular shaped section.

The portions 13 are advantageously perforated with mud passage holes 50. The holes 50 assure that mud can circulate more freely in the internal volume 4 of the parallelepiped 6 and is consequently more easily sucked outside the internal volume 4.

The guide hopper 10 is fixed to the parallelepiped forming the mud collection element 2, the second ends of the guide walls being inserted in the top face 7 of the mud collection element 2.

The face 11 forms a first orifice of the hopper 10.

The face 12 forms a second orifice of the hopper 10.

The second orifice 12 is the same size as or is narrower than the orifice 5 through which the vibrator of the mud collection element 2 passes, because the hopper 10 is inserted into the parallelepiped forming the mud collection element 2.

The face 11 and the base 12 are sized so that the vibrator can pass through, as will be explained below.

Advantageously, the face 11 is wider than the base 12, so that it is easy to pour gravel into the hopper 10, as will be described below.

As can be seen particularly well on FIGS. 7 and 10, the control device 1 includes a mud evacuation module 15, removing mud from the mud collection element.

The evacuation module 15 comprises at least one pipe 16, one end 17 of which is located in the inside volume 4 of the mud collection element 2 and the other end 18 is located outside the internal volume of the mud collection element and can be connected to a mud suction pump

In the embodiment illustrated, the general shape of the evacuation module 15 is a Y and it comprises two pipes 16, the end 17 of which plunges into the internal volume 4 of the parallelepiped 2 and that come together in a single pipe 19.

Preferably, the control device 1 comprises a gravel filter, as has already been described in detail with reference to the first embodiment.

Similarly, the control device 1 advantageously comprises a mud pump, as has already been described in detail with reference to the first embodiment.

As can be seen on FIGS. 6 to 10, the control device 1 also comprises a retaining structure 20 previously described with reference to the first embodiment.

As can be seen on FIGS. 6 to 10, the control device 1 comprises at least one sling point 25, and preferably four sling points 25 located at the tops of the rectangle formed by the bars 23, for transport of the control device 1.

On FIGS. 6 to 10, the leak tightness device comprises at least one insertion wall corresponding to the side walls 8 a, 8 b, 8 c and 8 d of the parallelepiped 6.

Nevertheless, there can be several variants of the leak tightness device, as described above.

When in the working position to make a compacted gravel column in the ground, the control device 1 is place on the ground, as already mentioned for the first embodiment.

The face 11 and the base 12 of the guide element 10, and the passage orifice 5 of the upper face 7 of the mud collection element 2 are facing the ground.

The four lateral faces are partially forced into the ground, while the bars 21 a, 21 b, 21 c, 21 d of the retaining structure 20 lie on the ground.

FIGS. 11 and 12 illustrate a control system 30 comprising a control device 1 according to this invention.

The control system 30 comprises a traction means 31, advantageously of the caterpillar type.

As can be seen on the figures, the system 30 comprises a gravel storage tank 32 and a gravel conveyor belt 33 between the storage tank 32 and the gravel and mud control device 1.

The control device 1 is fixed to a front part of the system 30, close to one end of the belt 33.

The belt 33 moves and forms a gravel conveyor from the storage tank 32 to the guide wall 3 of the control device 1.

The storage tank 32 advantageously comprises a hopper to guide the gravel as it is poured into the storage tank 32.

FIGS. 11 and 12 illustrate a third embodiment of the control device 1.

As can be seen on FIGS. 11 and 12, the control device 1 comprises a mud collection element 2 in the form of an open cylinder above which there is a single guide wall 3.

Obviously, the system 30 can also include a control device according to the first or the second embodiment.

Advantageously, the system 30 comprises a remote control unit for the traction means 31, for example to enable autocontrol of the system 30 using a geopositioning system known in itself to an expert in the subject.

Another purpose of the invention is a system 60 illustrated in FIG. 13 including the control device 1 according to either of the embodiments, and at least:

-   -   a flow meter 61 to measure the volume of evacuated mud, and/or     -   a built-in gravel volume or mass measurement instrument 62, for         example of the laser type or differential weighing type known to         an expert in the subject, so that the quantity of gravel poured         into the gravel column can be known in real time.

The system 60 also advantageously comprises a data collection and recording system 63, for data supplied by the flow meter 61 and/or the gravel mass measurement instrument 62.

FIGS. 14, 15 and 16 illustrate a method of constructing a compacted gravel column 40 using a drilling system 41 fitted with a vibrator 42, using a gravel and mud control system 1.

The device 1 is preferably implanted in the ground, in other words the lateral faces 8 a to 8 d of the parallelepiped 6 or the lateral face 8 of the cylinder 6 are pushed at least partially into the ground. This implantation stabilizes the control device 1 and assures that the device 1 remains leak tight, improving mud retention.

The method then includes a step to move the vibrator 42 from a rest position to a ground drilling position.

In its rest position illustrated in FIG. 14, the vibrator 42 suspended from a carrier 46, is placed at a height

In the ground drilling position, the vibrator 42 penetrates the ground 44 at location 43.

The displacement step of vibrator 42 comprises a step during which the vibrator 42 passes through the control device 1 before penetrating into the ground 44.

As can be seen on FIG. 15, the method includes a drilling step during which the vibrator 42 moves in the ground 44, creating an excavation 47.

As can be seen on FIG. 16, once the vibrator 42 has reached a determined depth, the method includes a step in which gravel is inserted in the control device 1, during which the gravel is guided by the guide wall(s) in the excavation.

As can be seen in FIGS. 15 and 16, the method includes a step to collect mud obtained after injection of water during the soil drilling step using the vibrator in the internal volume 4 of the control device 1.

Mud is drawn in by a mud pump 48 outside the control device 1.

According to a first variant, the method includes a preliminary to position the control device 1 at a location 43 on the ground 44 to be drilled above a location in which a gravel inclusion 45 will be placed.

For example, this is the case with the self-contained and/or self-controlled system 30.

According to a second variant, the control device 1 is raised at the same time as the vibrator using slings 25 and the assembly is displaced by the carrier 46 to the installation position.

In other words, according to the second variant, the vibrator 44 and the device 1 are fixed to the carrier 46 during the preliminary positioning step.

During the preliminary step, the vibrator is preferably retained in the device 1, as can be seen on FIG. 14.

Thus, the device and the method according to the invention can collect mud outside the drilling zone while precisely pouring the necessary and sufficient quantity of gravel into each excavation.

Obviously, the different embodiments and the different variants of this invention can be combined.

In particular, the control device 1 according to one of the three embodiments or one of the two variants is advantageously included in the system 30 and/or the system 60.

Similarly, the usage method described is applicable to the control device 1 either by itself, or as part of the system 30 and/or the system 60. 

1. A gravel and mud control device for a compacted gravel column made by wet construction using a drilling system fitted with a vibrator, comprising; a mud collection element defining an internal volume capable of collecting mud and fitted with an orifice through which the vibrator will pass, and at least one gravel guide wall leading to the orifice through which the vibrator will pass in the mud collection element.
 2. The control device of claim 1, further comprising: a guide element provided with said at least one guide wall, a first orifice, and a second orifice, the second orifice being the same size as or narrower than the orifice through which the vibrator of the mud collection element passes, the first and second orifices being sized so that the vibrator can pass through them.
 3. The control device of claim 1, in which the collection element comprises a top face.
 4. The control device of claim 2, in which the general shape of the guide element is a truncated pyramid.
 5. The control device of claim 1, further comprising: a mud evacuation module, for removing mud from the mud collection element.
 6. The control device of claim 5, in which the evacuation module comprises: at least one pipe, one end of which is located in the inside volume of the mud collection element and the other end is located outside the internal volume of the mud collection element and can be connected to a mud suction pump.
 7. The control device of claim 6, comprising the mud suction pump.
 8. The control device of claim 1, further comprising: a sealing device between the ground and the mud collection element.
 9. The control device of claim 8, in which the sealing device comprises at least one insertion wall of the control device into the ground.
 10. The control device of claim 1, further comprising: at least one sling point.
 11. A gravel and mud control system for a compacted gravel column made by wet construction using a drilling system provided with a vibrator, said system comprising: a control device including: a mud collection element defining an internal volume capable of collecting mud and fitted with an orifice through which the vibrator will pass, and at least one gravel guide wall leading to the orifice through which the vibrator will pass in the mud collection element; a gravel storage tank; and a gravel conveyor belt from the storage tank to the gravel and mud control device.
 12. The control system of claim 11, further comprising: a traction means.
 13. The control system of claim 11 further comprising at least one of: a flow meter to measure the volume of evacuated mud, and a gravel volume or mass measuring instrument, built into the control device.
 14. The control system of claim 13, further comprising: a data collection and recording system, for data supplied by at least one of the flow meter (61) and the gravel mass measurement instrument.
 15. A method of constructing a compacted gravel column using a drilling system fitted with a vibrator, comprising: a step to displace the vibrator from a rest position into a soil drilling position, characterised in that the displacement step includes a step during which the vibrator passes through a gravel and mud control device.
 16. The construction method of claim 15, further comprising: a step before the gravel and mud control device is put into position at a location on the ground to be drilled above a location in which gravel inclusion (47) will be made, the control device being moved independently of the vibrator or moved fixed to the vibrator.
 17. The construction method of claim 15, further comprising: a step in which the ground is drilled by the vibrator and a step in which gravel is added into the gravel and mud control device, during which the gravel is guided by said at least one guide wall in the hole drilled by the vibrator.
 18. The construction method of claim 15, further comprising: a step to collect mud obtained after injection of water during the soil drilling step using the vibrator in the internal volume of the gravel and mud control device.
 19. The construction method of claim 18, further comprising: a step to pump mud outside the gravel and mud control device.
 20. The control device of claim 1, further comprising: a flow meter to measure the volume of evacuated mud, and a gravel volume or mass measuring instrument, built into the control device. 